Abstract: A fuel charging system which injects nitrous oxide into the engine of a high performance vehicle to provide an instant burst of power to the vehicle. A nitrous oxide supply line feeds nitrous oxide under pressure from a supply container thereof into the vehicle engine through a spray bar. A normally closed solenoid valve controls the flow of nitrous oxide into the vehicle engine through the supply line. The supply line also is connected to a vent tube having a normally open solenoid valve controlling the flow of nitrous oxide thereto. The vent valve communicates with a one-way low pressure actuated check valve and vents any nitrous oxide leaking past the closed solenoid control valve into the atmosphere to prevent the harmful buildup of nitrous oxide in the engine.